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Introduction: The increasing number of geriatric traumatology cases has intensified the need to reliably and objectively evaluate local bone quality, the latter poses a decisive factor for the choice of an optimal approach to treat osteoporotic fractures. Osteodensitometry imaging techniques are not routinely available in acute operative settings, nor do they provide objective information on local bone properties specifically needed for the prognosis of implant stability., Materials and Methods: This study sought to verify ex vivo the feasibility and sensitivity of a novel method for the determination of local bone strength in the acute operative setting (intraoperative osseomechanical strength measurement; IOSM) that is based on the principle of material displacement resistance against the force of a rotary indenter. Samples consisted of human femoral heads obtained after total hip replacement. Comparisons were made with results obtained via conventional dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (qCT)., Results: Regression analyses of the results showed a highly significant correlation between the IOSM and the control methods (r = 0.61 and r = 0.56; p < 0.01), indicating that this new approach qualifies as a reliable tool for the intraoperative evaluation of the intrinsic local bone strength., Conclusions: The intraoperative integration of this method may support surgeon on taking proper decisions in terms of optimal surgical approaches and prevention of complications inherent to osteoporotic bone.

Purpose: Greater trochanteric pain syndrome (GTPS) is a condition resulting in lateral hip pain, most commonly caused by tendinosis or tear of the gluteus medius and minimus tendons, and greater trochanteric bursitis. Our aim was to assess pelvic parameters and proximal femoral anatomy in patients suffering from surgical-stage GTPS compared with a control group., Methods: This retrospective, case-control study assessed 43 patients suffering from GTPS, matched according to age, gender, body mass index and level of sport and physical activity to 43 control patients, between 2013 and 2018. Pelvic parameters, including pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS), and proximal femoral anatomy, including femoral offset (FO) and neck-shaft angle (NSA), were measured using the EOS Imaging™ system., Results: GTPS patients had a significantly lower mean (± SD) SS than control patients (33.1 ± 10.4 vs. 39.6 ± 9.7°, respectively; p < 0.05). There was no significant difference in PT (21.3 ± 7.1 vs. 19.0 ± 7.2°), PI (53.5 ± 11.6 vs. 57.7 ± 10.5°), FO (40.4 ± 8 vs. 42.2 ± 6.8°) or NSA (125.1 ± 5.8 vs. 124.4 ± 4.7°). There was no difference in lower back pain symptoms in a subgroup analysis of GTPS patients., Conclusions: Sacral slope was lower in patients with surgical-stage GTPS than in asymptomatic hip patients, using the EOS Imaging™ system.

Purpose: Due to improved prosthesis designs and surgical techniques, indications for total hip arthroplasty (THA) now include younger and more active patients. Preserving bone stock and soft tissue in these patients is paramount to allow for future revision. Designed for anatomical reconstruction, short femoral stems have the potential to reduce adaptive bone loss and stress shielding. To confirm this, we evaluated bone remodeling around a short femoral stem and the accuracy of hip joint reconstruction., Methods: This prospective observational study involved 46 patients with short-stem THA for clinical and radiographic analysis. We evaluated bone remodeling by Gruen zone using dual-energy X-ray absorptiometry in 45 patients and assessed the accuracy of hip joint reconstruction using caput-collum-diaphyseal angles. Additionally, we reported functional scores and pain., Results: Patients were followed for a mean of 24.1 (SD 2.2) months. Bone mineral density increased mainly in the lateral region (Gruen zones 2 and 3) and in the distal-medial region (Gruen zone 5), suggestive of lateral loading. Most caput-collum-diaphyseal angles remained stable after surgery, especially in patients with varus hips. Harris Hip Scores improved significantly, from 57.2 (SD 20.0) pre-operatively to 97.2 (SD 4.0) at 24 months post-operatively (P < 0.0001). Finally, we encountered one peri-operative dislocation but no post-operative complications., Conclusion: Short femoral stems successfully limited stress shielding and minimized periprosthetic bone loss without compromising primary stability. We were able to accurately reconstruct anatomical relationships in most patients. Finally, excellent clinical outcomes and low complication rates confirmed the favourable results of short-stem THA., Trial Registration: DRKS00017076.

Introduction: The Masquelet procedure proved its efficiency in treating infected nonunion filling bony gaps up to 25 cm. Yet the use of local antibiotics is still questionable in the daily practice with lack of evidence regarding its usefulness in controlling infection. An experimental rat model is put in place to study the antibacterial properties of the induced membrane produced during the first stage of Masquelet., Method: Twenty-three-month-old wistar male rats are inoculated with a 0.5 mL solution of 10^8 CFU/mL MRSA over a critical fracture done on the right femur. Six weeks later, remaining 11 rats exhibiting signs of a chronic infection with a sinus tract and oozing pus along with radiological nonunion are used for a first stage Masquelet procedure. They are randomly divided into two groups with six rats having no local antibiotic in the cement mixture and five rats having 3 g of vancomycin mixed with gentamycin loaded cement. Six weeks later (twelve weeks from baseline), all eleven rats are euthanized and blood samples for C-reactive protein are withdrawn. The induced membrane is identified and resected along with bone fragments and sent for cultures and pathology., Results: MRSA is isolated in the cultures of all six rats in the first group where no local antibiotic was added. Altered polymorphonuclears with abscess and pus are noted on four of six pathology samples. However in the second group where local antibiotics were added, three out of five rats exhibited eradication of MRSA (p = 0.034) and all samples did not exhibit clear infection signs on pathology. A pyo-epithelioid over a foreign body reaction is seen predominantly in this group demonstrating a regenerative process., Discussion: The induced membrane does not have antimicrobial properties capable of overcoming an infected nonunion on its own. When local antibiotics were added during the first stage of the Masquelet procedure, new bone formation occurred indicating the need to control an infection in order for bone union to occur., Conclusion: Local antibiotics use in adjunction to extensive debridement is advisable during the first stage of a Masquelet procedure for an infected nonunion.

Purpose: The purpose of this study was to check the concept of the cementless Metha® short hip stem in order to find out whether proximal physiological load transfer can be achieved., Methods: Fourty-three patients were included. Epidemiological factors were established. The Harris Hip Score was determined and measurement of bone mass density as well as osteodensitometric and radiological measurements was carried out pre-operatively, post-operatively, and after six, 12, 24, and 36 months., Results: Harris Hip Score improved from 55.9 ± 12.4 pre-operatively to 94.8 ± 8.2 after 36 months (p < 0.001). After initial reduction of bone density in zones 1 and 7 up to six months post-operatively, there was a steady approximation of bone density to the initial values (p < 0.05)., Conclusion: The Metha® short hip stem shows good clinical results. Furthermore, there is an increase of bone density in the proximal zones 1 and 7 between six and 36 months serving as a sign of physiological load transfer.

Purpose: To compare longitudinal growth and cam deformity of the proximal femur after treatment for slipped capital femoral epiphysis (SCFE) with one screw versus two smooth pins., Methods: We studied 43 patients (29 males, 14 females; mean age, 12.1 years; range, 9.5-14 years) with idiopathic unilateral SCFE treated with in situ fixation with one cannulated screw (group A, n = 23) or two smooth pins (group B, n = 20). Anteroposterior and frog-leg radiographs of the pelvis were evaluated for each patient at initial presentation, post-operatively and at physeal closure. Longitudinal growth was evaluated using the femoral neck length (FNL), the caput-collum-diaphyseal (CCD) angle, and the articulo-trochanteric distance (ATD). Cam deformity was assessed using the anterior offset α-angle and the head-neck offset ratio (HNOR). The mean follow-up was 5.1 years (range, 4-7 years)., Results: Postoperatively, the mean CCD angle was 138.3°, the mean α-angle was 66.1° and the mean HNOR was - 0.030. At physeal closure, mean CCD angle significantly decreased to 133.6°, mean α-angle significantly reduced to 52.1°, and mean HNOR significantly improved to + 0.039. CCD, FNL, ATD, α-angle, and HNOR were not different between groups., Conclusions: One screw or two smooth pins result in similar longitudinal growth and deformity of the proximal femur after SCFE. The femoral head-neck junction remarkably improves until physeal closure; however, residual cam deformity is not avoided after in situ pinning. The complication rate with smooth pins is higher.

Purpose: This study investigated whether Escherichia coli-derived bone morphogenetic protein (BMP)-2 (E-BMP-2) adsorbed onto β-tricalcium phosphate (β-TCP) granules can induce bone regeneration in critical-size femoral segmental defects in rabbits., Methods: Bone defects 20 mm in size and stabilized with an external fixator were created in the femur of New Zealand white rabbits, which were divided into BMP-2 and control groups. E-BMP-2-loaded β-TCP granules were implanted into defects of the BMP-2 group, whereas defects in the controls were implanted with β-TCP granules alone. At 12 and 24 weeks after surgery, radiographs were obtained of the femurs and histological and biomechanical assessments of the defect area were performed. Bone regeneration was quantified using micro-computed tomography at 24 weeks., Results: Radiographic and histologic analyses revealed bone regeneration in the BMP-2 group but not the control group; no fracturing of newly formed bone occurred when the external fixator was removed at 12 weeks. At 24 weeks, tissue mineral density, the ratio of bone volume to total volume, and volumetric bone mineral density of the callus were higher in the BMP-2 group than in control animals. In the former, ultimate stress, extrinsic stiffness, and failure energy measurements for the femurs were higher at 24 weeks than at 12 weeks., Conclusion: E-BMP-2-loaded β-TCP granules can effectively promote bone regeneration in long bone defects.

Background: Biomechanical evidence suggests that the anterolateral structures of the knee may be important restraints against anterolateral rotatory instability (ALRI) in the setting of anterior cruciate ligament (ACL) injury., Objective: To describe the anatomy and presence of injury of the capsule-osseous layer of the iliotibial band (CITB), the iliotibial band, and its deep distal femoral attachments in patients with a 'normal' knee (no pivot-shift bone marrow edema (BME) pattern) and patients with a pivot-shift BME pattern indicative of a pivot-shift injury associated with ACL tears., Methods: Group 1: 20 consecutive patients with no MRI evidence of pivot-shift injury and group 2: 20 consecutive patients with a pivot-shift BME pattern on MRI were identified. Retrospective consensus analysis of the anatomy and appearances of the CITB and the 'proximal' and 'epicondylar' distal femoral attachments of the ITB was performed for each MRI by two experienced musculoskeletal radiologists., Results: The positive predictive value (PPV) of CITB injury for pivot-shift ACL injury was 74%, negative predicted Value (NPV) was 80%. The PPV for injury of the 'proximal' ITB femoral attachment with pivot-shift ACL injury was 93%, NPV was 84%. The PPV for 'epicondylar' iliotibial femoral attachment injury was 62%, NPV was 45%., Conclusions: Injury of the CITB and 'proximal' deep femoral attachments of the ITB are good markers for ACL injury even in the absence of a Segond fracture and should be evaluated on all MRIs as they may prove important in the further management of ALRI.

Introduction: In last three decades, total hip replacement in young patients became an habitual procedure. Principles of bone preservation are pushing many surgeons to implant conservative femoral components in patient younger than 65 years. Despite an overall good survivorship and clinical outcomes of conservative implants, failed cases are reported and the need to revise a conservative femoral component became an occasional procedure (with high prevalence of failed resurfacing implants)., Methods: During conservative femoral component revisions, we analyzed proximal bone stock preservation, considering the type of original component removed, aetiology of failure, timing of revision, and femoral explantation technique., Results: We identified four patterns of proximal femoral changes (types I-IV). We suggest, for each of them, a revision strategy directed toward a "conservative revision procedure" using conservative or primary component. Out of our 21 cases, none underwent further revision due to mechanical failure (follow-up ranging from 6 to 152 months, mean 54 months). We had two cases of re-operation: one for early septic loosening and one for prosthetic modular neck fracture., Conclusions: If literature offers well-established guidelines to femoral revision of conventional stems, there is, on the other hand, a lack of data about revision strategies in presence of failed conservative implants. Although the mean follow-up of our procedures is still too short (4.5 years) to give final conclusions, we would leave a message: a conservative hip arthroplasty is not a "one time" opportunity for young and active people. A "conservative revision" is a valid option for at least a part of them, when an early failure of primary procedure occurred.

Purpose: Bone remodeling around the femoral component after total hip arthroplasty (THA) is considered to be an important factor in long-term stability and seems to be strictly related to the stem design, coating, and fixation. Stress shielding, micro-movement, and high intra-articular fluid pressure might activate macrophages and osteoclasts, causing progressive bone density decreases. Here we analyze the bone mineral density (BMD) around a cementless femoral stem during a 20-year period to better understand the adaptive bone changes around such implants during long-term follow-up., Methods: In this retrospective study, 14 patients treated by THA were reviewed from a cohort of 84. Clinical evaluation with Harris Hip Score and radiographic assessment were performed throughout a 20-year follow-up. To evaluate the bone remodeling around the stem, we monitored the femoral BMD in four regions of interest with a dual-energy X-ray absorptiometry (DEXA) post-operatively and at one, two, three, five and 20 years of follow-up., Results: The main BMD changes between the post-operative examination and the 20-year follow-up varied between + 11.19% and + 24.30%. Patients with signs of loosening, low Harris Hip Scores, and pain showed decreasing BMD values., Conclusions: The correlation between the clinical result and BMD values could suggest DEXA results as a predictor of implant loosening or longevity.

Introduction: Femoral shaft fractures with third fragments have a high non-union rate, which may reach 14%. This study aims to assess the impact of the radiological features of the third fragment, evaluated on post-operative X-rays, on the outcome of femoral shaft fractures type 32-B managed with intramedullary nailing, in order to obtain an algorithm which could predict the fracture healing time., Materials and Methods: We have retrospectively evaluated a series of 52 patients. On post-operative X-rays, four radiological parameters were evaluated: the third fragment angle, the fracture gap, the third fragment size, and the mean third fragment displacement. All the patients underwent a radiologic follow-up at one, two, three, six, nine and 12 months post-operatively, to assess the bone healing. The patients were then divided into three groups, according to the fracture healing time: within six months (group A), between six and 12 months (group B), or fracture non-union after 12 months (group C)., Results: In 28 patients, out of 52 (53.85%), the fracture healing was observed at 6-month follow-up; in 18 patients, out of 52 (34.62%), the fracture healed within 12 months after trauma; and in six patients, out of 52 (11.54%), no fracture healing was observed at 12-month follow-up. The mean third fragment size was significantly different in each group (p < 0.05), while the mean third fragment displacement was significantly higher in group C, compared with group A (p = 0.0006) and group B (p = 0.0027). In group B, a positive correlation was found between the fracture healing time and the mean third fragment size (R = 0.594, p = 0.036); in group C, the fracture union time was positively related to the third fragment size (R = 0.689, p = 0.013) and the mean third fragment displacement (R = 0.7107, p = 0.006). Regression analysis showed that the third fragment size and the mean third fragment displacement are the most important features which affect the fracture healing time., Conclusions: The third fragment size (cutoff 40 mm) is the leading parameter to influence the fracture healing within or in more than six months. The mean third fragment displacement (cutoff 12 mm); on the other hand, impacts on the fracture delayed rather than absent healing.

Introduction: Aim of this study was to investigate the incidence and extent of femoral shortening in non-geriatric patients after internal fixation of femoral neck fractures in relation to the clinical outcome at mid-term follow-up., Materials and Methods: Reviewing our admission data, we identified non-geriatric patients (18-65 years) with femoral neck fractures treated with either dynamic hip screw or cancellous screws between 2007 and 2015. Patients were then contacted and invited to a follow-up clinical investigation including whole-leg standing X-rays., Results: A total of 40 patients with a mean age at surgery of 52 ± 9 years returned for the follow-up examination. Overall, 31 patients (77.5%) had undergone a dynamic hip screw fixation, while 9 patients were treated with cancellous screws (22.5%). The median follow-up time was 65.5 months (5.5 years). We observed shortening of the ipsilateral femur neck in the majority of cases (92.5%). Still, functional outcome in the overall study population was excellent with a median Harris Hip Score of 96., Conclusions: Femoral neck shortening is common in non-geriatric patients after internal fixation of femoral neck fractures. Nonetheless, observed excellent functional outcome at mid-term follow-up supports joint-preserving strategies in non-geriatric femoral neck fractures.

Purpose: As an antioxidant molecule, hydrogen has been received much more attention and reported to be used as the treatment strategy for various diseases. In this study, we hypothesize that systemic delivery of hydrogen saline water may improve the reservation of bone tissue in the tibias and femurs of osteoporotic rats caused by diabetes mellitus (DM), which is characterized by increased levels of oxidative stress and overproducing reactive oxygen species (ROS)., Methods: The animals were divided into three groups of 12 animals and lavaged with normal saline (normal control and DM), or hydrogen saline water (DM + HRS). General status, blood glucose level, tibial and femoral mechanical strength, and micro-CT scans of the proximal tibia were recorded and analyzed., Results: After 12 weeks, the glucose level was significantly decreased in the DM + HRS group compared with that of the DM group. Micro-CT scans showed that bone volume/total volume, connectivity density, trabecular thickness, and trabecular number were significantly increased compared with the DM group. Mechanical results of energy, stiffness and elastic modulus in the DM + HRS group were significantly higher than in the other groups for the tibia and femur., Conclusions: The results indicate that the systemic delivery of hydrogen saline water, which is safe and well tolerated, preserves bone volume and decreases fracture risks in streptozotocin-induced diabetic status rats, whose bone structure or inherent material properties of bone tissues are changed.

Purpose: Three-dimensional bioactive scaffolds are useful tools for stem cell implant in tissue-engineering. For chondral and subchondral repair, the chondroinductive and osteoinductive property of a scaffold is a major challenge. The scaffolds that aim to osteogenic differentiation have been well studied. However, cartilage cells can hardly be induced for osteogenesis, and monophase scaffolds cannot ideally repair both cartilage and subchondral defects at the same time., Methods: We developed a novel biphase composite scaffold and observe its application osteochondral defects. We combined the advantages of silk-fibroin/chitosan (SF/CS) scaffold in chondrogenic differentiation and the silk-fibroin/chitosan/nano-hydroxyapatite (SF/CS/nHA) scaffold in osteogenic differentiation and bone regeneration, and synthesized a SF/CS-SF/CS/nHA scaffold, which contained both the chondrocytic phase (SF/CS) and the osteoblastic phase (SF/CS/nHA)., Results: The biphase scaffold exhibited a porosity ratio around 90% and a water absorption ratio about 822%. A similar degradation property to traditional monophase scaffolds was observed. Bone mesenchymal stem cells (BMSCs) showed a good proliferation on this scaffold. Expression of two types of collagen was inducable for BMSCs on the scaffold. Neoformative extracellular matrix integrated with the scaffold was observed by the scanning electron microscope. When implanted in the lesion site in the rabbit femur with cartilage injury, mixing and filling function were exerted by the cell-scaffold constructs (CSCs). Micro-CT scanning revealed both chondral and subchondral layers were repaired. Moreover, type I and II collagens were both expressed in the implanted CSCs., Conclusions: Chondral and subchondral repair can be achieved using the biphase scaffold implant that permits both chondrogenesis and osteogenesis from BMSCs. This approach has the potential to be clinically used for tissue engineering implantation.

The results of epidemiological, clinical, and in vivo and in vitro experimental studies on the effect of opioid analgesics on bone are inconsistent. The aim of the present study was to investigate the effect of morphine (an agonist of opioid receptors), buprenorphine (a partial μ opioid receptor agonist and κ opioid receptor antagonist), and naloxone (an antagonist of opioid receptors) on the skeletal system of female rats in vivo. The experiments were carried out on 3-month-old Wistar rats, divided into two groups: nonovariectomized (intact; NOVX) rats and ovariectomized (OVX) rats. The bilateral ovariectomy was performed 7 days before the start of drug administration. Morphine hydrochloride (20 mg/kg/day s.c.), buprenorphine (0.05 mg/kg/day s.c.), or naloxone hydrochloride dihydrate (2 mg/kg/day s.c.) were administered for 4 weeks to NOVX and OVX rats. In OVX rats, the use of morphine and buprenorphine counteracted the development of osteoporotic changes in the skeletal system induced by estrogen deficiency. Morphine and buprenorphine beneficially affected also the skeletal system of NOVX rats, but the effects were much weaker than those in OVX rats. Naloxone generally did not affect the rat skeletal system. The results confirmed the role of opioid receptors in the regulation of bone remodeling processes and demonstrated, in experimental conditions, that the use of opioid analgesics at moderate doses may exert beneficial effects on the skeletal system, especially in estrogen deficiency., Competing Interests: Compliance with ethical standards The protocol for the experiments on animals was approved by Local Ethics Commission, Katowice, Poland. Conflict of interest The authors declare that they have no conflict of interest.

Introduction: Trabecular properties in osteonecrosis of the femoral head (ONFH) are altered for bone volume and structure in the femoral head and proximal femoral canal. We analysed the periprosthetic bone mineral density (BMD) as a correlate to bony ingrowth in patients with ONFH who received a cementless THA., Materials and Methods: We performed a matched-pair analysis of 100 patients with ONFH (n = 50) and primary osteoarthritis (n = 50) who received the same, unilateral cementless THA. We compared the periprosthetic BMD 5 years after surgery by means of dual energy X-ray absorptiometry (DXA) analysing the seven femoral regions of interest (ROIs) according to Gruen., Results: Within the ONFH group, significantly lower BMD values were found in the ROI 1 and 7 (p < 0.05). No statistically significant difference was found for ROIs 2-6., Conclusions: An altered periprosthetic bone stock in the proximal femur in patients with prior ONFH might be a possible risk factor for premature loosening of the femoral stem in THA. Surgeons need to consider coating and fixation philosophy of cementless implants when choosing the right stem for patients with ONFH.

Background: The requirements for treatment of femoral fractures are increasing with the rising age of the patients. The aim of this study was to evaluate femoral stiffness and the fracture risk after inserting different implants and implant combinations., Methods: A total of 48 cadaveric femors were harvested and 8 groups were randomized on the basis of the bone mineral density (BMD). Different osteosyntheses following prosthetic stem implantation (hip and knee prostheses) were performed and compared with native femurs. All specimens were biomechanically tested in a four-point bending until fracture., Results: The insertion of a femoral stem decreases the stiffness by approximately 33%. Ipsilateral retrograde nailing reduces the force to failure even more. This instable situation can be stabilized by a lateral locking compression plate. The most stable situation occurred in the presence of two cemented stems., Conclusion: Taken together these results clearly indicate that a hip prosthesis significantly weakens the femur, whereas two stems produce the most stable situation at all. The situation of a hip prosthesis and an retrograde nail should be avoided or covered by a bridging-osteosynthesis. In clinical practice an extramedullary fixation technique for distal femoral fractures should be preferred.

Aims: We systematically investigated the effect of combined use of low-intensity pulsed ultrasound (LIPUS) and bone mesenchymal stem cells C3H10T1/2 on bone-defect healing., Methods: C3H10T1/2 cells were first induced into a stationary phase by incubation with low fetal bovine serum (5 ml/l) for five days and then sonicated with LIPUS for ten minutes once every day for five consecutive days. The same LIPUS treatment combined with C3H10T1/2 cells, which were incubated in regular fetal bovine serum (10 ml/l) were used to aid femoral fracture healing in Sprague-Dawley rats during four consecutive weeks. C3H10T1/2 cell proliferation activity was detected by MTT assay. Cell-cycle changes were determined, and cell proliferation index was calculated using flow cytometry. Bone reparation was evaluated by X-ray imaging and hematoxylin and eosin (H&E) staining during the healing process., Results: LIPUS promoted C3H10T1/2 cell proliferation, the mechanism of which was possibly the up-regulation of Bmi-1 gene expression. At the end of week two after combined use of LIPUS and C3H10T1/2, the femoral gap was reduced on X-ray images. According to H&E staining results, new bone had homogeneous and similar density compared with normal surrounding bone after combined use of LIPUS and C3H10T1/2. At the end of week four, bone defects could not be observed by X-ray in all four groups and repaired bone substance in all four groups could be observed by H&E staining., Conclusions: LIPUS treatment effectively promotes C3H10T1/2 cells to enter the growth/split phase from the stationary phase. This process enhances cell proliferation, which consequently promotes bone-defect healing.

Purpose: To investigate the effects of titanium implants functionalised with collagen type I (TiColl) on bone regeneration and osteointegration in a healthy and osteopenic rat animal model., Method: TiColl screws were implanted into the femoral condyles of healthy and osteopenic rats and compared with acid-etched titanium (Ti) screws. The osteointegration process was evaluated by a complementary approach combining microtomographic, histological, histomorphometric and biomechanical investigations at four and 12 weeks., Results: The TiColl screw also ensured a greater mechanical stability; the push-out values for TiColl screws increased from four to 12 weeks (+28 %). The energy necessary to detach the bone from the screw was significantly higher for TiColl-functionalised screws in comparison to Ti screws (+23 %) at 12 weeks. Histomorphometric investigation revealed that total bone-to-implant contact was higher in TiColl screws in comparison to Ti screws (P < 0.05) and at epiphyseal level, increased bone-to-implant contact was found with TiColl screws in comparison to Ti screws (P < 0.05) in an ovariectomy (OVX) condition. A significant increase in the measured total bone ingrowth from four to 12 weeks was detected for both materials, but more significant for the TiColl material (P < 0.0005). Finally, bone ingrowth in the TiColl group was significantly higher (P < 0.005) in comparison to that of Ti screws in the SHAM condition at metaphyseal level at 12 weeks., Conclusion: The present results showed that TiColl is effective in promoting implant osteointegration even in compromised bone.

Purpose: The purpose of this study was to evaluate whether femoral antetorsion affects the range of motion (ROM) following total hip arthroplasty (THA) using 3D dynamic analysis., Methods: Using 3D computed tomography (CT) data of 71 patients (71 hips) who underwent THA, we calculated antetorsion of the femoral neck, flexion range of motion (Flex ROM), internal rotation (Int-R) and external rotation (Ext-R). Evaluation of the relationship between antetorsion, ROM and the impingement site was performed. As for implant position, anteversion of the femoral implant was set to be the same as natural antetorsion of the femoral neck, and the acetabular component was set 45° of total anteversion in all cases., Results: We found a significant decrease in Flex ROM and Int-R inversely proportional to femoral antetorsion. In patients with lower antetorsion, Flex ROM and Int-R decreased due to bony impingement (the anterior great trochanteric region of the femur impinges on the anteroinferior edge of the anteroinferior iliac spine). However, in Ext-R, there was no relationship between ROM and femoral antetorsion., Conclusions: We demonstrated that lower femoral antetorsion substantially affects Flex ROM and Int-R due to bony impingement. For these patients, consideration must be given to retaining femoral anterior offset in THA.

Purpose: Besides the long-leg standing X-ray film focusing on static standing mechanical alignment of the lower extremity, dynamic alignment from full extension to 90° flexion after total knee arthroplasty (TKA) is rarely mentioned. Computer-assisted surgical technology enables surgeons to measure and assess knee behaviour during surgery. This study was designed to analyse the influences of femoral rotation on dynamic alignment of the lower extremity in TKA., Methods: Seventy-six consecutive patients with end-stage knee osteoarthritis were enrolled. External rotation osteotomy of the distal femur during TKA was completed according to the pre-operative external rotation angle (ERA), intra-operative transepicondylar axis (TEA) and anteroposterior (AP) line. Passive dynamic alignment of the lower extremity during knee flexion was recorded. The variation trend of hip-knee-ankle (HKA) alignment and the influences of femoral external rotation osteotomy were analysed., Results: Postoperative deviation of HKA alignment from 0° to 90° flexion was associated with the rotational alignment of the femoral component (r = -0.769, p < 0.001). Variation trend of HKA alignment during knee flexion tended to be varus, valgus and neutral according to the selected angle of external rotation osteotomy of the distal femur., Conclusion: External rotation osteotomy of the distal femur played a crucial role in determining dynamic HKA alignment in TKA.

Purpose: The purpose of this study was to examine the concept of proximal load initiation of a total short-stemmed hip arthroplasty (Metha BBraun, Aesculap, Tuttlingen, Germany) on the basis of bone variations by means of osteodensitometric dual energy X-ray absorptiometry and radiologic measurements., Methods: After power analysis 40 patients were included in this study. DXA examination, radiological and clinical follow-up was performed pre-operatively and postoperatively. Socio-demographic relevancies of bone progression and radiological changes were raised epidemiologically and clinically., Results: Improvement of the Harris hip score from 54.7 points preoperative to 96.7 points postoperative was detected (p < 0.01). Loss of summarized overall net average bone mass density (netavg BMD) could only be manifested after six months compared to the netavg BMD of the postoperative measurement (p < 0.01). After six and 12 months BMD atrophy was shown mainly in regions of interest (ROI) 1, 4 and 7. Positive correlations between changes of BMD and age, male sex and BMI were detectable. No stem had to be revised., Conclusions: The Metha implant shows excellent osseointegration at the coated area of the stem without factors of aseptic loosening in the short term. This study shows that parameters like age, sex and BMI influence BMD progression and stress shielding. Metha implant shows excellent results especially in young patients with good bone stock.

Purpose: Premature physeal closure of the proximal femoral physis has been reported in Legg-Calve-Perthes Disease (LCPD). However, the timing of its occurrence had not yet been reported. We proposed (1) to determine the timing of premature physeal closure in unilateral LCPD with serial radiographic evaluation, and (2) to evaluate the relationship between the premature physeal closure and Herring classification, leg-length discrepancy (LLD), Stulberg classification, and trochanteric overgrowth., Methods: We performed a retrospective study with serial radiographs of 27 patients diagnosed with LCPD. The difference in the timing of physeal closure between the hips was calculated. The involved hip was classified according to Herring classification. The LLD and ATD index at latest follow up was measured. The mean values were calculated and statistical comparison of variables was done using the Fisher's exact test., Results: The mean difference of physeal closure at the involved hip compared to the uninvolved side was 3.5 years (range, two to five years). Hips demonstrating premature physeal closure were associated with Herring B/C and C (p = 0.01) and LLD >1 cm (p = 0.02). There is no correlation between Stulberg classification, trochanteric overgrowth and premature physeal closure (p = 0.06 and p = 0.19)., Conclusions: We may expect premature physeal closure of the proximal femoral physis in patients with LCPD to occur 3.5 years earlier than normal hips. Presence of premature physeal closure can be an adjunct diagnostic tool in the prognostication of LCPD outcomes. Future studies directed toward premature physeal closure in LCPD and associated growth disturbances are necessary.

Purpose: In order to evaluate new therapeutic approaches to human osteonecrosis of the femoral head (ONFH), this study proposed to improve the existing animal model by developing a new surgically induced pig model., Methods: First, ONFH was induced with an easy and minimally invasive technique: cryogenic insult with repeated freeze-thaw cycle. Then, to compare and improve the efficacy of this first method, we combined the cryogenic insult to vascular coagulation of the posterior circumflex vessels., Results: Cryoinjury with repeated freeze-thaw cycle alone is sufficient to induce, three weeks postsurgery, a subchondral necrosis as confirmed by magnetic resonance imaging (MRI) and histological analysis. However, a bone regeneration began at four weeks and was complete at eight weeks. To optimise this result, we combined cryoinjury with posterior circumflex vessel coagulation and observed the persistence of ONFH, with progression to collapse at 14 weeks postinduction., Conclusions: Cryoinjury associated with partial vascular coagulation is sufficient to obtain localised and sustainable necrosis in the subchondral area of the femoral head, reproducing all stages of the human disorder. The co-analysis by MRI and histology allowed us to confirm that the classic T1- and T2-weighted hyposignal regeneration front around a fatty high T1-weighted signal observed by MRI indicate signs of induced osteonecrosis. Our results indicate that our pig model induces all stages of human ONFH, which can be followed by MRI, making it relevant for clinical trials.

Purpose: To investigate the effects of a trial femoral component on the intraoperative joint gap and intraoperative joint gap kinematics throughout the range of knee motion in minimally invasive surgery-total knee arthroplasty (MIS-TKA) with the gap technique., Materials and Methods: A total of 103 patients [15 men (15 knees) and 89 women (89 knees)] aged 50-88 years (mean 74.8 years) who received MIS-TKA with the gap technique were included. The intraoperative joint gap differences (90° flexion gap distance minus 0° extension gap distance) with and without the trial femoral component were compared. Subsequently, the intraoperative joint gap kinematics at 0°, 45°, 90°, and 120° with the trial femoral component were investigated., Results: The intraoperative component gap difference (4.4 ± 2.7 mm) was larger than the estimated joint gap difference (1.2 ± 1.9 mm) (p < 0.01). The mean intraoperative component gap distances at 0°, 45°, 90°, and 120° of knee flexion were 14.7 ± 2.6, 19.0 ± 3.2, 19.2 ± 3.4, and 16.6 ± 3.3 mm, respectively. The intraoperative component gap distance increased significantly from 0° extension to 90° of knee flexion (p < 0.01), and then decreased significantly toward deep knee flexion at 120° (p < 0.01)., Conclusions: The trial femoral component influenced the intraoperative gap measurements, and increased the intraoperative gap difference. The joint gap kinematics with the trial femoral component were not constant throughout the range of knee motion, even if the appropriate joint gaps in extension and flexion were achieved. For acquisition of constant stability throughout the knee motion, the present results should be taken into account by surgeons performing MIS-TKA with the gap technique.

Purpose: This study aimed to propose a technique to quantify dynamic hip screw (DHS®) migration on serial anteroposterior (AP) radiographs by accounting for femoral rotation and flexion., Methods: Femoral rotation and flexion were estimated using radiographic projections of the DHS® plate thickness and length, respectively. The method accuracy was evaluated using a synthetic femur fixed with a DHS® and positioned at pre-defined rotation and flexion settings. Standardised measurements of DHS® migration were trigonometrically adjusted for femoral rotation and flexion, and compared with unadjusted estimates in 34 patients., Results: The mean difference between the estimated and true femoral rotation and flexion values was 1.3° (95% CI 0.9-1.7°) and -3.0° (95% CI - 4.2° to -1.9°), respectively. Adjusted measurements of DHS® migration were significantly larger than unadjusted measurements (p = 0.045)., Conclusion: The presented method allows quantification of DHS® migration with adequate bias correction due to femoral rotation and flexion.

Objective: To evaluate the heat effects of radiofrequency ablation (RFA) on normal bone by mechanical testing, MRI, and histology., Materials and Methods: The institutional animal care and use committee approved the animal study. Thirty-two adult Japanese white rabbits were included in our study. Bone biopsy needles were inserted from the distal end of the right (RFA side) and the left (control side) femurs using a fluoroscopic guide. A 17-gauge internally cooled RFA electrode with a 2-cm active tip was inserted through the needle to the right femur, and RFA was performed for 12 min using a 200-W generator. Animals were divided into four groups and 8 animals from each group were euthanized on day 1, day 7, day 30, and day 60 after RFA. MRI was performed prior to euthanasia. Three-point bending test was performed to measure flexural strength. Student's t test was used to evaluate for significant differences between RFA and control side for each group. Femurs underwent histological examination by hematoxylin and eosin staining after the bending test., Results: MRI showed a high-intensity rim around the bone on T2WI. Three-point bending test showed no statistically significant differences (P < 0.05) between the RFA and the control side in any of the groups. Histologically, osteocytes of cortical bone showed cell death, but the lamellar structure was preserved in all groups and bone remodeling was observed., Conclusion: Heat by RFA did not change normal bone strength within 2 months, despite the heat effects in the cortical bone and cell death.

Purpose: This study was conducted to assess the posterior inclination of the contralateral femoral epiphysis in patients with unilateral slipped capital femoral epiphysis (SCFE)., Methods: The posterior sloping angle (PSA) was measured using lateral radiographs in 67 patients with a unilateral SCFE and in 41 age-matched normal controls. A symptomatic epiphyseal slip was defined as the development of SCFE., Results: The contralateral PSA in SCFE patients was more widely distributed and significantly larger compared to controls (15.0° vs. 9.0°, p < 0.0001). Forty-seven hips (70.1%) had a PSA of greater than 12.8°, which was +2SD of the control hips. Of the 65 hips excluding the two cases with prophylactic pinning, 11 hips (16.9%) eventually developed a contralateral SCFE during adolescence and their PSA at the initial visit was significantly larger compared to patients without a contralateral SCFE (18.0° vs. 14.3°, p < 0.005) with a cutoff value of 19°., Conclusions: These findings suggested the possibility of bilateral hip involvement in SCFE patients. Hips with greater degrees of PSA (> 19°) are likely to become symptomatic.

Objective: The purpose of this study was to investigate the effect of rotational deformities on patellofemoral alignment using the dynamic magnetic resonance imaging method on patients whose femur fractures were treated with intramedullary locking nails., Methods: The dynamic patellofemoral magnetic resonance imaging results of 33 patients (5 females and 28 males) were reviewed. The mean age of the patients was 36.3 (range 19-61) years. The mean follow-up was 30.2 months (range 24-38). All the patients were given Kujala patellofemoral clinical evaluation scores at the latest follow-up. Those with less than 10° of rotational deformity in either direction were classified as Group A, those with more than a 10° of internal rotation deformity as Group B and more than a 10° of external rotation deformity as Group C. The three groups were then compared regarding to clinical scores. Patellofemoral parameters of operated and contralateral side were also compared in each group., Results: There were 14 (42.4 %) patients in Group A, 12 (36.4 %) patients in Group B and 7 (21.2 %) patients in Group C. The mean patella score in Group C (74 ± 7.02) was significantly lower when compared with Group B (87.6 ± 9.9) and group A (90.6 ± 6.1) (p < 0.05). In Group C patients, medial patellar tilt was detected when compared with the intact side. There were no significant changes in patellofemoral position in either Group A or Group B., Conclusion: The results of this study revealed that more than 10° of external rotation deformity could cause a detoriation in the patellofemoral scores. Anatomic reduction of the fracture site should be performed as soon as possible and external rotational deformities should especially be avoided in order to prevent patellofemoral malalignment.

Purpose: The number of candidates for a total hip arthroplasty (THA) is steadily increasing, while the average patient age is decreasing for primary THA. The rise in THA is mainly due to excellent clinical outcomes and the extended longevity of modern implants. Short stem arthroplasties with predominantly metaphyseal fixation such as the Metha® stem are suggested for young patients. It is hypothesised that the more physiological load transfer of these devices reduces stress shielding, which in turn may reduce the risk of aseptic loosening. However, patients with femoral deformities often require a deviation of the resection height. To this end, our aim was to evaluate how resection height influences strain patterns in order to characterise possible limits for short stem implantation., Methods: Biomechanical testing using ten strain gauges on synthetic bone illustrated the strain patterns of three different resection heights (0, +5 and +10 mm) for the Metha stem., Results: The greatest differences in strains were displayed at the "high" (most proximal) resection height (+10 mm) when compared to the non-implanted strain pattern. At the medial calcar, the strain was 143% for +10 mm, 96% for +5 mm and 94% for 0 mm. Overall, discrepancies were less for deeper resections., Conclusions: The deeper the resection, the more similar the strain patterns are when compared to a non-implanted synthetic bone. Changes in strain patterns are induced by variation in the varus/valgus positioning of the implant and by different offsets.

Objectives: Osteogenesis imperfecta (OI) is an inherited disorder characterized by increased bone fragility with recurrent fractures that leads to skeletal deformities in severe cases. Consequently, in most OI patients, the hip is the only reliable measuring site for estimating future fracture risk. The aim of the study was to assess the applicability of hip structure analysis (HSA) by DXA in adult patients with osteogenesis imperfecta., Materials and Methods: We evaluated bone mineral density (BMD) and hip structure analysis (HSA) by DXA, including cross-sectional area (CSA), cross-sectional moment of inertia (CSMI) and femoral strength index (FSI) in 30 adult patients with different types of OI and 30 age-matched healthy controls (CO). The OI total group (OI-tot) was divided into two subgroups: the mild OI I group (OI-I) and the more severe OI III and IV group (OI-III-IV)., Results: The mean neck BMD of OI-I and OI-III-IV were significantly lower compared to CO (-15.9 %, p < 0.005 and -37.5 %, p < 0.001 respectively). Similar results were observed at trochanter and total hip. CSA and the CSMI value were significantly lower for OI-I (-23.2 %, p < 0.001) and OI-III-IV (-45.9 %, p < 0.001) in comparison to CO. In addition, significant differences were found between the mild OI-I and the severe OI-III-IV group (-29.6 %, p < 0.05). FSI was significantly decreased in the OI-III-IV (25.7 %, p < 0.05) in comparison to the CO. Furthermore, significant correlations between BMD and HSA and between HSA and height and weight were found in osteogenesis imperfecta and controls., Conclusion: BMD measurement in osteogenesis imperfecta patients is very critical. The combination of BMD and geometric structural measurements at the hip in osteogenesis imperfecta patients may represent an additional helpful means in estimating bone strength and fracture risk.

Introduction: The present study investigates the reaction of bone density as well as the possible factors influencing this reaction following a cement-free total knee arthroplasty (TKA)., Materials and Methods: Osteodensitometry scan data from 50 prospective patients with TKA was evaluated. The patients were split into two groups according to the number of follow-up investigations undertaken. No patient included in the study had received medication to increase bone density. To identify the changes in periprosthetic bone density, dual energy X-ray absorptiometry (DXA) bone density measurements in defined regions of interest (ROI) were performed over a period of 24 months postoperative. The test parameters included gender, severity of arthrosis, as well as the metric parameters T-score, body mass index, cortical bone marrow index, and the varus alignment for the respective patient., Results: The most significant changes in bone density were recorded within the first 3 months postoperative, in particular, the highest bone density loss was found in the region of the proximal medial tibia. Moreover, significant gender-specific associations regarding changes in bone density were established., Conclusion: Finally, results achieved in the present study demonstrate that the fundamental classification in defined ROI proved to be functional and effective.

Introduction: Superporous hydroxyapatite (HAp-S) is a novel bone substitute that contains three-dimensionally interconnected macropores with micropores, which stimulate bone ingrowth into the material., Method: We investigated the in vivo behaviour of HAp-S by comparing its bioactivity and biomechanical properties with beta-tricalcium phosphates (β-TCP). HAp-S or β-TCP was implanted in the lateral femoral condyle of rabbits. In vivo bioactivity of each material, including bone ingrowth and material resorption, was quantitatively evaluated by micro-CT and the ultimate compressive strength of the bone-material composite was also measured. Micro-CT showed that bone ingrowth in the HAp-S group significantly increased over time, while no significant increase was observed after 8 weeks in the β-TCP group., Results: Although both materials showed gradual material resorption, β-TCP resorption was significantly greater than HAp-S. The ultimate compressive strength in the HAp-S group significantly increased over time up to six times its original value, while there was no significant increase in the β-TCP group. These results show that HAp-S resorption is concurrent with bone ingrowth, resulting in increasing compressive strength over 12 weeks. On the other hand, β-TCP resorption is fast but unaccompanied by bone ingrowth; consequently, it remains relatively fragile at least in the early period after implantation. Although these highly porous materials themselves are structurally and mechanically similar, there are significant differences in in vivo behaviour depending on the material composition., Conclusion: These findings should be kept in mind when choosing the highly porous ceramics.

Introduction: Cerclages regain interest due to a rising number of periprosthetic fractures. The contact distribution at the circumferential cerclage-bone interface is still unknown. Local interface pressure depends on the amount of contact area. Cortical damage at the interface would provoke cerclage loosening. Therefore, the contact area, the bone pressure along the interface and the cortical resistance underneath loaded cerclages were determined in an ex vivo model., Materials and Methods: Human diaphyseal femoral bone was used with differing cross-sectional geometry. Bone contact points of fixed 1.5 mm wire and 1.7 mm cable cerclages were identified from axial radiographs. Pressure distribution at the cerclage-bone interface was recorded with a pressure-measuring film using a distraction setup with two cortical half shells. Bone shells with installed cerclages were separated with up to 400 N force and were subsequently analyzed histologically to detect cortical damage., Results: Both cerclage types exhibited a point contact fixation with non-loaded spanned zones in-between. Cables cover larger contact areas. Both cerclages exhibited an inhomogeneous interface pressure distribution depending on the bone surface geometry. Histology revealed intact cortical bone without cortical affection after loading of both cerclage types., Conclusion: Point contact fixation of the cerclages installs non-loaded, spanned zones where the periosteum is not compressed, rendering a strangulation of the blood supply unlikely. Cortical bone withstands static concentric pressure produced by the cerclage. Cortical groove formation is attributed to instability under functional load and not to weakness of the cortex itself.

Introduction: Osteoarthritis is a degenerative joint disease characterized by progressive erosion of the articular cartilage. The sites of erosion of articular cartilage have been reported, but no explanation for this particular pattern has previously been suggested., Aims: To analyze the gross features of lesions, together with their frequency of occurrence and situation, and wear relationship with individual body profile., Materials and Methods: Data collected from the dissection of 102 cadavers at a tertiary hospital., Results: Wear patterns on the tibial surface show that the areas involved in the majority of cases include middle medial and middle lateral regions of the tibial plateau. There also seemed to be a strong correlation between age, body mass index and the wear pattern. The incidence of posteromedial erosions on the tibial plateau was mainly seen in the ACL-deficient knee. Also, incidence of lateral meniscus tears was found to be higher in the ACL-deficient knees., Conclusion: In osteoarthritis of the knee joint, the middle third of both the femoral and tibial articular surfaces is most commonly involved in wears, followed by anteromedial and posterolateral compartments both for tibial and femoral surfaces. The wear patterns in the ACL-deficient knee changes due to altered loading characteristics.

Introduction: The aim of our study was to investigate in vitro and in a new in vivo rat model for impaired bone healing whether a low dose BMP-2 preparation in fibrin would be equivalent or better than the combination of collagen and a high dose of BMP-2 which is currently in clinical use., Materials and Methods: In a 14 day period we compared the in vitro release kinetics of an absorbable collagen sponge (ACS) with 72 μg rhBMP-2 in the BMPC group and fibrin matrix with 10 μg rhBMP-2 in the BMPF group. In our in vivo experiment a critical sized osteotomy was performed in the rat femur, which was filled with a spacer, inhibiting bone formation for a period of 4 weeks. In a second operation this spacer was removed and the test item was applied into the defect. We compared the BMPF and BMPC groups with the ACS alone, FIBRIN alone and the EMPTY (4w/8w) control groups. 4 and 8 weeks after the second operation, specimens were analysed by X-ray and μCT imaging. Mechanically stable femurs were biomechanically evaluated., Results: Cumulative BMP-2 release was five times higher in the BMPF group than in the BMPC group during the observation period. μCT analysis revealed that both the extent of bone union and the bone volume were significantly higher in the group with a lower dose of BMP-2 in fibrin matrix than in the groups without BMP-2 treatment. However there was no statistically significant difference between the BMPF and BMPC groups., Conclusion: We conclude that fibrin matrix is an excellent carrier for BMP-2 and that it provides equivalent results with a sevenfold lower dose of BMP-2 compared with ACS.

Purpose: Periprosthetic bone loss around the femoral stem is frequently found after total hip arthroplasty. We have shown that periprosthetic bone mineral density (BMD) loss using the triple tapered stem is consistently much less in comparison with the straight type component. In this study, we compared periprosthetic BMD change with clinical factors., Methods: Postoperative dual-energy X-ray absorptiometry was evaluated at follow-up. BMD was determined based on seven Gruen zones. We further compared BMD with clinical examination: body mass index (BMI), age, Harris hip score (HHS) or University of California at Los Angeles (UCLA) activity rating score., Results: Periprosthetic BMD loss of the triple tapered stem was maintained. Especially, BMD in Gruen zone 1 which was maintained at 96% in comparison with the straight tapered stem. We compared the BMD change with clinical factors. There is no correlation between BMD and BMI, age or HHS. However, we found significant correlation between BMD and UCLA activity rating score in Gruen zones 1 and 2 of the triple tapered stem. Further, the correlation coefficient was increased at 48 months in comparison with 24 months., Conclusion: The cementless triple tapered stem maintains periprosthetic bone mineral density. Activity may reflect improving periprosthetic bone quality after THA using a triple tapered stem.

Renal insufficiency induces cortical bone loss in rats. The present study examined the influence of vitamin K(2) on renal function, cortical bone mass, and bone strength in rats with renal insufficiency. Thirty male Sprague-Dawley rats (8 weeks old) were randomized by the stratified weight method to the following three groups of 10 animals each: sham operation (control), 5/6 nephrectomy, and 5/6 nephrectomy + oral vitamin K(2) (menaquinone-4, menatetrenone, 30 mg/kg, 5 days/week). Treatment was initiated 10 days after surgery. After 6 weeks of treatment, samples of serum, urine, and bone (femur and tibia) were obtained. Renal function was evaluated, bone histomorphometric analysis was performed on the tibial diaphysis, and the bone mineral density (BMD) and mechanical strength of the femoral diaphysis were determined by peripheral quantitative computed tomography and a three-point bending test, respectively. Nephrectomy induced renal dysfunction, as indicated by increased levels of serum creatinine and urea nitrogen along with a decrease of creatinine clearance; and it also decreased BMD without significantly affecting bone strength at the femoral diaphysis. Vitamin K(2) improved renal function parameters but did not significantly influence BMD at the femoral diaphysis. However, vitamin K(2) decreased the bone marrow area of the tibial diaphysis and increased the stiffness of the femoral diaphysis. These findings suggest that administration of vitamin K(2) improves renal function and increases cortical bone strength without altering BMD in rats with renal insufficiency.

Purpose: In clinical and retrieval analyses, over-penetration of cement, incomplete seating of the prosthesis with a resultant polar cement mass, or both, have been associated with early femoral failures of resurfacing arthroplasties. We used human bone specimens to experimentally compare the initial stability of different cementing techniques., Methods: Twenty-six pairs of fresh frozen femora were prepared for resurfacing using original instruments (DePuy ASR). ASR femoral resurfacing prostheses were implanted using two different cementing techniques: (1) component filling and (2) cement applicator. Real-time measurements of pressure and temperature during implantation, analyses of cement penetration and micro motions under torque application were performed., Results: Applicator use reduced significantly the cement penetration depth (9.2 mm vs 5.3 mm with the applicator, p = 0.001), polar mantle (8.1 mm vs 2.6 mm, p = 0.008), cement defects (3.7 mm vs 0.1 mm, p = 0.008) and interface temperatures (40.3°C vs 33.1°C, p < 0.001 ). Initial rotational stability showed statistically significant less extreme values with the cement applicator technique (range 3.4-51.7 m°/Nm, 11.0-29.7 m°/Nm, p = 0.024)., Conclusions: The cement applicator technique significantly reduces cement defects, incomplete seating, over-penetration and interface temperatures with a more consistent initial stability of the ASR femoral resurfacing prostheses.

Endochondral bone formation requires new blood vessel formation, and endothelial progenitor cells (EPCs) may play a role in this process. Endothelial colony-forming cells (ECFCs), one subtype of EPCs, isolated from the microvasculature of rat lungs, exhibited cell surface antigen markers and gene products characteristic of endothelial cells and displayed high proliferative potential and an ability to form vessel-like network structures in vitro. The aim of this study was to evaluate whether ECFCs facilitate bone healing during fracture repair and stimulate bone regeneration. When type I collagen sponge containing ECFCs were surgically wrapped around the fractured femurs of rats, newly formed bone mineral at the site of fracture was 13% greater (P = 0.01) and energy to failure was 46% greater (P = 0.01) compared to sponge-wrapped fractures without ECFCs. When ECFCs in type I collagen sponge were surgically implanted into the bone defective area, more new vessels formed locally in comparison with sponge-alone controls and new bone tissues were seen. Further, co-implantation of ECFCs and hydroxyapatite/tricalcium phosphate (HA/TCP) scaffolds at the bone defective sites stimulated more new bone tissues than HA/TCP scaffold alone. These results show that cell therapy with vessel wall-derived ECFCs can induce new vessel formation, stimulate new bone formation, and facilitate bone repair and could be a useful approach to treat non-union fractures and bone defects.

Introduction: The standard treatment of femoral diaphyseal fractures is intramedullary nailing. Torsion error remains a largely unsolved problem. We hypothesized that femoral malrotation would change the coronal alignment of the lower extremity and the center of force (COF) in the tibiofemoral joint as compared to the native state., Method: Ten cadaveric legs were used. Intraarticularly placed sensor foil was used to measure contact pressures for each condyle. The resultant pressure of this two-force measurement was calculated as the COF for the joint. Mechanical axis was defined by the navigation system. Two novel devices were used: (1) to simulate bodyweight with leg attachment and fixation to the anterior pelvis and (2) to fix the femur at various degrees of malrotation. A mid-diaphyseal osteotomy was performed and the distal fragment was rotated both internally and externally in 5° increments to a maximum of 25°. COF and axial alignment were assessed at each step with application of a half-bodyweight specific to each specimen., Results: Internal rotation resulted in valgus deviation of the mechanical axis and a shift in COF towards the lateral condyle (P < 0.05). External rotation caused varus deviation and switched COF towards the medial condyle (P < 0.05). This study shows that femoral malrotation has a significant effect on mechanical axis alignment and force vectors within the knee. Correlation with clinical outcomes is necessary and further research into minimizing such errors of torsion is warranted., Conclusion: Torsion errors are not merely cosmetic issues, but may result in further morbidity, such as varus or valgus deformity and shifting of the COF, which may lead to joint arthrosis.

Objective: Bone bars (BB) are struts of normal trabecular bone that cross the medullary portions of the metaphysis and diaphysis at right angles to the long axis of the shaft. The purpose of this investigation was to determine whether the presence of bone bars (BB) identified on radiographs of the proximal femurs and tibia, predict lower bone mineral density (BMD) as evaluated with dual-energy x-ray absorptiometry (DXA) in the lumbar spine, total hip, or femoral neck., Materials and Methods: A total of 134 sequential DXA patients underwent radiography of the pelvis, hips, and both knees. The radiographs were evaluated for the presence of BB by two musculoskeletal radiologists who were blinded to DXA results. A t test was used to evaluate the relationship of BB to BMD and a Chi-square test was used to determine if BB were equally distributed among the categories of normal BMD, low bone mass (osteopenia), and osteoporosis., Results: BB were associated with lower BMD at all measured sites. BB at the intertrochanteric and proximal tibial sites were the most predictive of low BMD while supraacetabular and distal femur BB were less predictive. Osteoporosis or osteopenia is seen in 60-91% of those with BB depending on the side and reader. It is only seen in about 40% of those without BB., Conclusions: We conclude that the presence of BB suggest decreased BMD and when correlated with other clinical information, might support further evaluation of BMD.

Introduction: This study was designed to evaluate the incidence of femoral malrotation in bilateral femoral shaft fractures., Materials and Methods: All closed bilateral femoral shaft fractures in patients aged 18 or over treated between April 2000 and December 2009 were included in the current study. All patients received a postoperative CT-scan to estimate femoral antetorsion and leg length. All bilateral fractures were treated with intramedullary nailing on a radiolucent table. Retrospectively, all patients were analyzed according to the following parameters: (1) femoral antetorsion of both limbs and antetorsion difference in degrees, (2) femoral length discrepancy (cm), (3) incidence of femoral malrotation >15°, (4) revision rate due to femoral malrotation., Results: A total of 24 patients (11 [45.8%] female; 13 [52.8%] male) with bilateral femoral shaft fractures were included in this study of average age 38 years (median 38 years, range 18-74 years). Clinically relevant malrotation (greater than 15°) was found in 10 cases (41.2%), whereas in 4 cases (40%) a revision surgery was required., Discussion: Bilateral femoral shaft fractures are associated with a high incidence of clinically relevant femoral malrotation over 15°. Measurement of intraoperative femoral antetorsion in bilateral femoral shaft fractures is quite difficult and currently only feasible postoperatively.

Introduction: A quantitative analysis of the response of proximal femur bone to implantation of revision stems with distal fixation and of the factors that affect that response has not previously been published., Materials and Methods: A prospective study of 138 stem revision operations involving replacement with cementless, modular, titanium revision stems with distal fixation (Revitan, Zimmer GmbH, Winterthur, Switzerland) was designed to assess Barnett and Nordin scores at the proximal femur obtained immediately after surgery and at a 3-year follow-up examination in order to analyze bone regeneration in the proximal femur and associated response-modifying factors., Results: In general, a bone formation with increase of the Barnett and Nordin score was observed. However, stress shielding occurred in cases of osteoporosis or more severe bone defects. A statistical analysis of possible factors that might affect the bone response revealed that the degree of bone regeneration was directly related to the Barnett and Nordin score obtained immediately post-surgery and the severity of the bone defect and only indirectly to the length of the stem, which is determined by the type of bone defect, and to the necessity of interlocking screws., Conclusion: Distally fixed titanium revision stems do not result in stress shielding per se. Proximal bone response depends mostly on the condition of the bone before and immediately after the operation and not, as stated in many reports, on surgical procedures such as method of approach or the thickness of the prosthesis.

We evaluated the contribution of lifestyle-related factors, calcaneal ultrasound, and radial bone mineral density (BMD) to cervical and trochanteric hip fractures in elderly women in a 10-year population-based cohort study. The study population consisted of 1,681 women (age range 70-73 years). Seventy-two percent (n = 1,222) of them participated in the baseline measurements. Calcaneal ultrasound was assessed with a quantitative ultrasound device. BMD measurements were performed at the distal and ultradistal radius by dual-energy X-ray absorptiometry. Forward stepwise logistic regression analysis was used to find the most predictive variables for hip fracture risk. During the follow-up, 53 of the women had hip fractures, including 32 cervical and 21 trochanteric ones. The fractured women were taller and thinner and had lower calcaneal ultrasound values than those without fractures. High body mass index (BMI) was a protective factor against any hip fractures, while low functional mobility was a risk factor of hip fractures. Specifically, high BMI protected against cervical hip fractures, while low physical activity was a significant predictor of these fractures. Similarly, high BMI protected against trochanteric fractures, whereas low functional mobility and high coffee consumption were significant predictors of trochanteric fractures. Cervical and trochanteric hip fractures seem to have different risk factors. Therefore, fracture type should be taken into account in clinical fracture risk assessment and preventative efforts, including patient counseling. However, the study is not conclusive due to the limited number of observed fractures during follow-up, and the results have to be confirmed in future studies.

Introduction: When highly conforming polyethylene inlays were introduced into total knee arthroplasty (TKA), they were characterized as adding anteroposterior stability to the reconstructed knee. The aim of this study was to examine the patellofemoral pressure with the designs of a highly conforming and a posterior stabilized inlay. The patellofemoral pressure depends among other factors on the anteroposterior stability of the knee joint., Materials and Methods: Eight fresh frozen human knee specimens underwent testing in a kinematic device. Knee motion was driven by a hydraulic cylinder at an extension moment of 31 Nm. The patellofemoral contact pressure was measured using a pressure sensitive film (Tekscan((R)), Inc., Boston, USA). First, this was assessed after implantation of a cruciate retaining (CR) TKA with a highly conforming polyethylene insert before and after resection of the posterior cruciate ligament. After that, the same measurements were performed with a similar posterior stabilized prosthesis., Results: Patellofemoral contact pressures in the CR prosthesis using the highly conforming inlay were not significantly different before and after resection of the posterior cruciate ligament. However, after implantation of a posterior stabilized prosthesis peak pressure was significantly lower [Mean: 6.12, (SD 2.37) MPa] in comparison to the highly conforming type [7.12, (SD 2.53) MPa, P < 0.01] at a preserved posterior cruciate ligament. Further to that, the mean contact pressure turned out to be lower with the posterior stabilized design (P < 0.006)., Conclusion: The results of this study suggest that a posterior stabilized prosthesis design reduces the patellofemoral peak and mean pressure in comparison with a high conforming design. The better reproducible femoral rollback with a posterior stabilized model at a tibial ventral shift could serve as a possible explanation.

Treatment of an underlying disease is often initiated after the occurrence of an osteoporotic fracture. Our aim was to investigate whether teriparatide (PTH 1-34) and strontium ranelate affect fracture healing in ovariectomized (OVX) rats when provided for the first time after the occurrence of an osteoporotic fracture. We combined the model of an OVX rat with a closed diaphyseal fracture. Sixty Sprague Dawley rats were randomly assigned to four groups. Fracture healing in OVX rats after treatment with pharmacological doses of strontium ranelate and PTH 1-34 was compared with OVX and sham-treated control groups. After 28 days, the femur was excised and scanned by micro computed tomography and the callus evaluated, after which biomechanical torsional testing was performed and torque and toughness until reaching the yield point were analyzed. Only treatment with strontium ranelate led to a significant increase in callus resistance compared to the OVX control rats, whereas both PTH 1-34 and strontium ranelate increased the bone volume/tissue volume ratio of the callus. The PTH 1-34-increased trabecular bone volume within the callus was even higher compared to sham. As for the callus tissue volume, the increase induced by strontium ranelate was significant, contrary to the changes induced by PTH. Callus in strontium ranelate-treated animals is more resistant to torsion compared with OVX control rats. To our knowledge, this is the first report of the enhancement of fracture healing by strontium ranelate. Because both treatments enhance bone and tissue volume within the callus, there may be a qualitative difference between the calluses of PTH 1-34- and strontium ranelate-treated OVX rats. The superior results obtained with strontium ranelate compared to PTH in terms of callus resistance could be the consequence of a better quality of the new bone formed within the callus.

We analysed 17 patients with primary malignant bone tumour of the femur who underwent limb salvage surgery with the total femoral custom mega prosthesis during the period 1994-2008. The patients were in the age group of 12-73 years, with a mean age of 30.94 years. There were 14 males. The most common diagnosis was osteosarcoma. The average follow-up period was 54.05 months with the longest being 168 months. The average Musculoskeletal Tumour Society (MSTS) functional score was 66.6%. The two- to 14-year overall survival was 82.4%. Three patients died of disease and one patient required amputation. Complications encountered were deep infection and dislocation of the prosthesis.

Objective: To evaluate bone density and associated factors in women with premature ovarian failure (POF) compared to age-matched women with normal ovarian function., Methods: A cross-sectional study of 50 patients with POF undergoing bone mineral densitometry was conducted, compared to 50 women paired by age who menstruated regularly., Results: In women with POF, the mean bone mineral density measured was 1.22 g/cm(2) at the spine and 0.92 g/cm(2) at the femur, values which were significantly lower than in the control group (P < 0.0001). Factors directly associated with bone density of the lumbar spine were age and with bone density of the femur were BMI and reproductive age., Conclusion: Young women with POF have a decrease in lumbar spine and femoral bone density. Age, reproductive age and BMI were the factors associated with BMD. These women need early investigation and treatment to prevent bone loss and minimize fracture risk in the future.

Study Question: Pathologic bone fractures in cryosurgery of bone tumors have been described in literature. This study utilizing a sheep model should prove the possible reduction of potential fracture while using a new miniature cryoprobe minimizing tissue damage and providing accurate control of the ablation process. Furthermore, postoperative histological changes should be investigated and the results correlated with the stability trials., Methods: In 24 sheep, ablation of the femur and the tibial bone on one side was carried out. Ablation of the right femur was limited to an area of 2 cm(2) with single cortical bone, whereas at the left tibia the whole proximal tibial plateau was included. The other side served as a control entity without cryoablation. After a period of 2, 4, and 6 months postoperative investigation of bending resistance of the femoral bone and of compression resistance of the tibial bone as well as histological findings were done in eight animals each., Results: After 2 months there was a significant difference (P < 0.05) regarding compression resistance between the treated and the contralateral tibia, whereas the bending resistance in the treated femur was slightly lower than on the contralateral side. After 4 and 6 months the cryo-treated part showed a tendency towards weakness. Histological findings showed bone necrosis with slight beginning repair after 2 months. Four and six months later, bone necrosis still existed with increasing development of woven bone and conversion into lamellar bone., Discussion: A thorough control of the freezing process and the low iatrogenous weakening of the bone due to placing the probe when modern miniature cryoprobes are used can minimize the risk of pathological postoperative fractures. However, at least 2 months after operation there is histological proof of bone healing with appropriate reduction of bone stability, which should be considered for the clinical application of this new technique.